The burden of prostate cancer among Veterans is substantial with over 200,000 survivors and 12,000 new diagnoses annually. Most men live with rather than die from this common disease making prostate cancer survivorship care especially important. Because of its leadership in chronic disease care and the proportion of older men served, the Veterans Health Administration (VHA) is well positioned to become one of the national leaders in prostate cancer survivorship care. However, the quality of Veteran prostate cancer survivorship care is largely unknown. In addition, there is poor consensus about whether primary care providers or cancer specialists should have primary responsibility for ongoing cancer surveillance and management of treatment-related side effects (e.g., incontinence, osteoporosis). Ultimately, the design and implementation of tools to optimize prostate cancer survivorship care rests upon understanding how responsibility for survivorship care is managed and the barriers to good survivorship care. This research program will improve our understanding of Veteran prostate cancer survivorship care and seek to improve it using state-of-the-art implementation science methods. This program has three aims. Aim 1: To examine variation in 2 key quality indicators of prostate cancer survivorship care. Using national VHA data (2005-2011), we will examine variation in the quality of prostate cancer survivorship care for cancer surveillance and bone density testing. Aim 2: To assess barriers and facilitators to delivering high quality prostate cancer survivorship care. Guided by theory, we will perform focus groups and interviews with primary care providers and prostate cancer specialists to better understand how to improve survivorship care. Aim 3: To develop, implement and pilot a theory-based intervention to improve the quality of prostate cancer survivorship care. We will use our findings to pilot an intervention that addresses quality gaps in cancer surveillance and bone density testing uncovered in Aim 1, in preparation for a randomized trial. Due to the expanding population of Veteran prostate cancer survivors, optimizing their quality of survivorship care is of the utmost importance. Our findings will inform models for cancer survivorship care across VHA and guide future implementation efforts to improve the quality of cancer care.